blob: 8a275157a3bb1b7927d268fae7d07455be5fa5bd [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* peer.c: Rx RPC peer management
2 *
3 * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/sched.h>
13#include <linux/slab.h>
14#include <linux/module.h>
15#include <rxrpc/rxrpc.h>
16#include <rxrpc/transport.h>
17#include <rxrpc/peer.h>
18#include <rxrpc/connection.h>
19#include <rxrpc/call.h>
20#include <rxrpc/message.h>
21#include <linux/udp.h>
22#include <linux/ip.h>
23#include <net/sock.h>
24#include <asm/uaccess.h>
25#include <asm/div64.h>
26#include "internal.h"
27
28__RXACCT_DECL(atomic_t rxrpc_peer_count);
29LIST_HEAD(rxrpc_peers);
30DECLARE_RWSEM(rxrpc_peers_sem);
31unsigned long rxrpc_peer_timeout = 12 * 60 * 60;
32
33static void rxrpc_peer_do_timeout(struct rxrpc_peer *peer);
34
35static void __rxrpc_peer_timeout(rxrpc_timer_t *timer)
36{
37 struct rxrpc_peer *peer =
38 list_entry(timer, struct rxrpc_peer, timeout);
39
40 _debug("Rx PEER TIMEOUT [%p{u=%d}]", peer, atomic_read(&peer->usage));
41
42 rxrpc_peer_do_timeout(peer);
43}
44
45static const struct rxrpc_timer_ops rxrpc_peer_timer_ops = {
46 .timed_out = __rxrpc_peer_timeout,
47};
48
49/*****************************************************************************/
50/*
51 * create a peer record
52 */
53static int __rxrpc_create_peer(struct rxrpc_transport *trans, __be32 addr,
54 struct rxrpc_peer **_peer)
55{
56 struct rxrpc_peer *peer;
57
58 _enter("%p,%08x", trans, ntohl(addr));
59
60 /* allocate and initialise a peer record */
Panagiotis Issaris0da974f2006-07-21 14:51:30 -070061 peer = kzalloc(sizeof(struct rxrpc_peer), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 if (!peer) {
63 _leave(" = -ENOMEM");
64 return -ENOMEM;
65 }
66
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 atomic_set(&peer->usage, 1);
68
69 INIT_LIST_HEAD(&peer->link);
70 INIT_LIST_HEAD(&peer->proc_link);
71 INIT_LIST_HEAD(&peer->conn_idlist);
72 INIT_LIST_HEAD(&peer->conn_active);
73 INIT_LIST_HEAD(&peer->conn_graveyard);
74 spin_lock_init(&peer->conn_gylock);
75 init_waitqueue_head(&peer->conn_gy_waitq);
76 rwlock_init(&peer->conn_idlock);
77 rwlock_init(&peer->conn_lock);
78 atomic_set(&peer->conn_count, 0);
79 spin_lock_init(&peer->lock);
80 rxrpc_timer_init(&peer->timeout, &rxrpc_peer_timer_ops);
81
82 peer->addr.s_addr = addr;
83
84 peer->trans = trans;
85 peer->ops = trans->peer_ops;
86
87 __RXACCT(atomic_inc(&rxrpc_peer_count));
88 *_peer = peer;
89 _leave(" = 0 (%p)", peer);
90
91 return 0;
92} /* end __rxrpc_create_peer() */
93
94/*****************************************************************************/
95/*
96 * find a peer record on the specified transport
97 * - returns (if successful) with peer record usage incremented
98 * - resurrects it from the graveyard if found there
99 */
100int rxrpc_peer_lookup(struct rxrpc_transport *trans, __be32 addr,
101 struct rxrpc_peer **_peer)
102{
103 struct rxrpc_peer *peer, *candidate = NULL;
104 struct list_head *_p;
105 int ret;
106
107 _enter("%p{%hu},%08x", trans, trans->port, ntohl(addr));
108
109 /* [common case] search the transport's active list first */
110 read_lock(&trans->peer_lock);
111 list_for_each(_p, &trans->peer_active) {
112 peer = list_entry(_p, struct rxrpc_peer, link);
113 if (peer->addr.s_addr == addr)
114 goto found_active;
115 }
116 read_unlock(&trans->peer_lock);
117
118 /* [uncommon case] not active - create a candidate for a new record */
119 ret = __rxrpc_create_peer(trans, addr, &candidate);
120 if (ret < 0) {
121 _leave(" = %d", ret);
122 return ret;
123 }
124
125 /* search the active list again, just in case it appeared whilst we
126 * were busy */
127 write_lock(&trans->peer_lock);
128 list_for_each(_p, &trans->peer_active) {
129 peer = list_entry(_p, struct rxrpc_peer, link);
130 if (peer->addr.s_addr == addr)
131 goto found_active_second_chance;
132 }
133
134 /* search the transport's graveyard list */
135 spin_lock(&trans->peer_gylock);
136 list_for_each(_p, &trans->peer_graveyard) {
137 peer = list_entry(_p, struct rxrpc_peer, link);
138 if (peer->addr.s_addr == addr)
139 goto found_in_graveyard;
140 }
141 spin_unlock(&trans->peer_gylock);
142
143 /* we can now add the new candidate to the list
144 * - tell the application layer that this peer has been added
145 */
146 rxrpc_get_transport(trans);
147 peer = candidate;
148 candidate = NULL;
149
150 if (peer->ops && peer->ops->adding) {
151 ret = peer->ops->adding(peer);
152 if (ret < 0) {
153 write_unlock(&trans->peer_lock);
154 __RXACCT(atomic_dec(&rxrpc_peer_count));
155 kfree(peer);
156 rxrpc_put_transport(trans);
157 _leave(" = %d", ret);
158 return ret;
159 }
160 }
161
162 atomic_inc(&trans->peer_count);
163
164 make_active:
165 list_add_tail(&peer->link, &trans->peer_active);
166
167 success_uwfree:
168 write_unlock(&trans->peer_lock);
169
170 if (candidate) {
171 __RXACCT(atomic_dec(&rxrpc_peer_count));
172 kfree(candidate);
173 }
174
175 if (list_empty(&peer->proc_link)) {
176 down_write(&rxrpc_peers_sem);
177 list_add_tail(&peer->proc_link, &rxrpc_peers);
178 up_write(&rxrpc_peers_sem);
179 }
180
181 success:
182 *_peer = peer;
183
184 _leave(" = 0 (%p{u=%d cc=%d})",
185 peer,
186 atomic_read(&peer->usage),
187 atomic_read(&peer->conn_count));
188 return 0;
189
190 /* handle the peer being found in the active list straight off */
191 found_active:
192 rxrpc_get_peer(peer);
193 read_unlock(&trans->peer_lock);
194 goto success;
195
196 /* handle resurrecting a peer from the graveyard */
197 found_in_graveyard:
198 rxrpc_get_peer(peer);
199 rxrpc_get_transport(peer->trans);
200 rxrpc_krxtimod_del_timer(&peer->timeout);
201 list_del_init(&peer->link);
202 spin_unlock(&trans->peer_gylock);
203 goto make_active;
204
205 /* handle finding the peer on the second time through the active
206 * list */
207 found_active_second_chance:
208 rxrpc_get_peer(peer);
209 goto success_uwfree;
210
211} /* end rxrpc_peer_lookup() */
212
213/*****************************************************************************/
214/*
215 * finish with a peer record
216 * - it gets sent to the graveyard from where it can be resurrected or timed
217 * out
218 */
219void rxrpc_put_peer(struct rxrpc_peer *peer)
220{
221 struct rxrpc_transport *trans = peer->trans;
222
223 _enter("%p{cc=%d a=%08x}",
224 peer,
225 atomic_read(&peer->conn_count),
226 ntohl(peer->addr.s_addr));
227
228 /* sanity check */
229 if (atomic_read(&peer->usage) <= 0)
230 BUG();
231
232 write_lock(&trans->peer_lock);
233 spin_lock(&trans->peer_gylock);
234 if (likely(!atomic_dec_and_test(&peer->usage))) {
235 spin_unlock(&trans->peer_gylock);
236 write_unlock(&trans->peer_lock);
237 _leave("");
238 return;
239 }
240
241 /* move to graveyard queue */
242 list_del(&peer->link);
243 write_unlock(&trans->peer_lock);
244
245 list_add_tail(&peer->link, &trans->peer_graveyard);
246
247 BUG_ON(!list_empty(&peer->conn_active));
248
249 rxrpc_krxtimod_add_timer(&peer->timeout, rxrpc_peer_timeout * HZ);
250
251 spin_unlock(&trans->peer_gylock);
252
253 rxrpc_put_transport(trans);
254
255 _leave(" [killed]");
256} /* end rxrpc_put_peer() */
257
258/*****************************************************************************/
259/*
260 * handle a peer timing out in the graveyard
261 * - called from krxtimod
262 */
263static void rxrpc_peer_do_timeout(struct rxrpc_peer *peer)
264{
265 struct rxrpc_transport *trans = peer->trans;
266
267 _enter("%p{u=%d cc=%d a=%08x}",
268 peer,
269 atomic_read(&peer->usage),
270 atomic_read(&peer->conn_count),
271 ntohl(peer->addr.s_addr));
272
273 BUG_ON(atomic_read(&peer->usage) < 0);
274
275 /* remove from graveyard if still dead */
276 spin_lock(&trans->peer_gylock);
277 if (atomic_read(&peer->usage) == 0)
278 list_del_init(&peer->link);
279 else
280 peer = NULL;
281 spin_unlock(&trans->peer_gylock);
282
283 if (!peer) {
284 _leave("");
285 return; /* resurrected */
286 }
287
288 /* clear all connections on this peer */
289 rxrpc_conn_clearall(peer);
290
291 BUG_ON(!list_empty(&peer->conn_active));
292 BUG_ON(!list_empty(&peer->conn_graveyard));
293
294 /* inform the application layer */
295 if (peer->ops && peer->ops->discarding)
296 peer->ops->discarding(peer);
297
298 if (!list_empty(&peer->proc_link)) {
299 down_write(&rxrpc_peers_sem);
300 list_del(&peer->proc_link);
301 up_write(&rxrpc_peers_sem);
302 }
303
304 __RXACCT(atomic_dec(&rxrpc_peer_count));
305 kfree(peer);
306
307 /* if the graveyard is now empty, wake up anyone waiting for that */
308 if (atomic_dec_and_test(&trans->peer_count))
309 wake_up(&trans->peer_gy_waitq);
310
311 _leave(" [destroyed]");
312} /* end rxrpc_peer_do_timeout() */
313
314/*****************************************************************************/
315/*
316 * clear all peer records from a transport endpoint
317 */
318void rxrpc_peer_clearall(struct rxrpc_transport *trans)
319{
320 DECLARE_WAITQUEUE(myself,current);
321
322 struct rxrpc_peer *peer;
323 int err;
324
325 _enter("%p",trans);
326
327 /* there shouldn't be any active peers remaining */
328 BUG_ON(!list_empty(&trans->peer_active));
329
330 /* manually timeout all peers in the graveyard */
331 spin_lock(&trans->peer_gylock);
332 while (!list_empty(&trans->peer_graveyard)) {
333 peer = list_entry(trans->peer_graveyard.next,
334 struct rxrpc_peer, link);
335 _debug("Clearing peer %p\n", peer);
336 err = rxrpc_krxtimod_del_timer(&peer->timeout);
337 spin_unlock(&trans->peer_gylock);
338
339 if (err == 0)
340 rxrpc_peer_do_timeout(peer);
341
342 spin_lock(&trans->peer_gylock);
343 }
344 spin_unlock(&trans->peer_gylock);
345
346 /* wait for the the peer graveyard to be completely cleared */
347 set_current_state(TASK_UNINTERRUPTIBLE);
348 add_wait_queue(&trans->peer_gy_waitq, &myself);
349
350 while (atomic_read(&trans->peer_count) != 0) {
351 schedule();
352 set_current_state(TASK_UNINTERRUPTIBLE);
353 }
354
355 remove_wait_queue(&trans->peer_gy_waitq, &myself);
356 set_current_state(TASK_RUNNING);
357
358 _leave("");
359} /* end rxrpc_peer_clearall() */
360
361/*****************************************************************************/
362/*
363 * calculate and cache the Round-Trip-Time for a message and its response
364 */
365void rxrpc_peer_calculate_rtt(struct rxrpc_peer *peer,
366 struct rxrpc_message *msg,
367 struct rxrpc_message *resp)
368{
369 unsigned long long rtt;
370 int loop;
371
372 _enter("%p,%p,%p", peer, msg, resp);
373
374 /* calculate the latest RTT */
375 rtt = resp->stamp.tv_sec - msg->stamp.tv_sec;
376 rtt *= 1000000UL;
377 rtt += resp->stamp.tv_usec - msg->stamp.tv_usec;
378
379 /* add to cache */
380 peer->rtt_cache[peer->rtt_point] = rtt;
381 peer->rtt_point++;
382 peer->rtt_point %= RXRPC_RTT_CACHE_SIZE;
383
384 if (peer->rtt_usage < RXRPC_RTT_CACHE_SIZE)
385 peer->rtt_usage++;
386
387 /* recalculate RTT */
388 rtt = 0;
389 for (loop = peer->rtt_usage - 1; loop >= 0; loop--)
390 rtt += peer->rtt_cache[loop];
391
392 do_div(rtt, peer->rtt_usage);
393 peer->rtt = rtt;
394
395 _leave(" RTT=%lu.%lums",
396 (long) (peer->rtt / 1000), (long) (peer->rtt % 1000));
397
398} /* end rxrpc_peer_calculate_rtt() */